The present invention relates to a power station switch having high nominal current, the switch comprising a break chamber containing a dielectric gas under pressure and mounted inside a protective sheath which may optionally carry a general flow of cooling air, and a radiator/heat-exchanger situated outside said sheath and connected to said break chamber in which said gas under pressure is put into continuous circulation.
Such a switch is known in particular from French patent document No. 2 199 182. In that known switch, the radiator/heat-exchanger is connected to the break chamber via two hollow support insulators which extend radially from the break chamber. Other hollow insulators for grounding also support the break chamber in the sheath. The number of insulators used in that arrangement is an important factor in the cost of the switch.
The object of the invention is to propose a solution for reducing the cost of such a switch fitted with a radiator/heat -exchanger.
To this end, the invention provides a power station switch having high nominal current, the switch comprising a break chamber containing a dielectric gas under pressure and mounted inside a protective sheath, and a radiator/heat-exchanger situated outside said sheath and connected to said break chamber and in which said gas under pressure is put into continuous circulation, wherein said gas under pressure as cooled in the radiator/heat-exchanger is returned to the break chamber via a metal case of the break chamber that is designed to be grounded. With this arrangement, the connection of the radiator/heat-exchanger to the break chamber requires the use of a single hollow insulator instead of two as in the prior art, thereby reducing the cost of making the switch. The case that is for grounding is typically the case which has installed therein the mechanism for driving the contacts of the break chamber.
In a particular embodiment of a switch of the invention, the break chamber extends axially along a vertical direction and has at its bottom end a bottom metal case for grounding and at its top end a top metal case connected to said radiator/heat-exchanger via a hollow insulator forming an insulating bushing. This in-line disposition of the connections between the outlet tube from the radiator/heat-exchanger, the bottom metal case of the break chamber, the top metal case of the break chamber, the hollow insulator forming an insulating bushing, and finally the inlet tube of the radiator/heat-exchanger, favors natural convection to drive circulation of the gas under pressure from the break chamber to the radiator/heat-exchanger and from the radiator/heat-exchanger to the break chamber along a vertical axis, and thus favors heat exchange. In addition, this disposition contributes to increasing the draw height for natural convection, thereby enhancing the speed at which the gas under pressure circulates in the radiator/heat-exchanger and in the break chamber.